Does Skill Cooldown Recovery Rate have Breakpoints?

For Frost Bomb, are there any Cooldown recovery breakpoints or is it just the more the better?

My belt has 15%, and I'm wondering if I should get boots with CDR as well or if it is overkill.

I dont think so.. duration is usually pretty accurate, displayed with two decimals (0.01 seconds). There are some breakpoints when in comes to fast triggering skills with CoC and stuff, because of server tick rate, but this is not the case..